Layer voltage divider with additional impedances

ABSTRACT

A layer voltage divider of the type having a resistance web and one or more additional impedances attached thereto, the divider comprising : one or several impedances on a supporting plate, laterally extending tabs provided on the impedance, an insulating layer covering the impedance or impedances to the exclusion of their taps, a resistance web being placed on the insulating layer and having taps, the taps of the resistance web being conductingly connected to the taps of the said one or more impedances.

United States Patent 15] 3,668,600 Schuberth et al., 1 June 6, 1972 [54] LAYER VOLTAGE DIVIDER WITH [56] References Cited ADDITIONAL IMPED C AN ES UNITED STATES PATENTS [7 2] Inventors: Christian Schuberth, 874 Herschfeld Bargstrasse l HerSchfeld y; woliEr. 1,02 l Miller X hard seigerwald Av, do DL Amunes 3,268,773 8/1966 Valley ..3 17/256 X Guimaraes, 503, Porto, Portugal Primary Examiner-E. A. Goldberg [731 Assigneez PREH Elektro-Felnmechanlsche Werke A"0,ney Stowe" & Stowe Jakob Preh. Nachfl, Bad Neustadt/Saale,

Germany [22] Filed: Nov. 16, 1970 [57] ABSTRACT [21] Appl. No.: 89,766

A layer voltage divider of the type having a resistance web and P one or more additional impedances attached thereto, the di- Forelgn Apphcat'on Pnomy Dam vider comprising one or several impedances on a supporting Nov. 22, 1969 Germany ..P 19 58 679.9 Plate, laterally extending labs provided on the impedance, an

' insulating layer covering the impedance or impedances to the 52 US. Cl ..338/320, 317/256, 323/78, exclusion of their tapee resistance Web being placed on the 338/254, 338/ l 28, 338/308, 317/ 101 C insulating layer and having taps, the taps of the resistance web [51] Int. Cl ..H01c 1/16 being eenduetingly eehneeted to the p of the Said one or [58] Field of Search ..338/254, 208, 320, 76, 120, more impedances- 338/122, 128; 323/76, 77, 78, 80; 317/256, 11001112 6Claims, snmwing Figures WAC BACKGROUNDOF THE INVENTION 1 The invention relates to a so-called layer voltage divider, i.e. a divider having a layer-, film-, webor coating-resistor. More particularly the invention relates to a layer voltage divider having at least one tap on its resistance web to which additional impedances are connected. Important applications of such voltage dividers are the sound-level adjusters with hearing-correct characteristic, in which one or several taps connect the resistance web to RC-sections and by which a predetermined frequency dependency of the voltage division is achieved. Dividers also belong to this group in which an exponential characteristic is achieved by being wired through taps of a linear resistance web with transverse resistors against the basis tap of the divider, wherein this principle is supplied also in connection with hearing-correct sound volume controls. Finally, a multiplicity of the voltage divider curves can be provided for the most varied application purposes by connecting resistors in parallel to the individual web sections of a voltage divider.

From German Utility Model 1,629,658 it is known to apply additional fixed resistors to the backside of a supporting plate of a rotary layer resistance, preferably by the same manufacturing method as the resistance web itself, and to connect them by means of rivets with the taps or the temiinals of the resistance web. I Moreover, it is already known from U.S. Pat. No. 3,320,571 for the formation of exponential voltage dividers to apply a well conducting layer on a support and on the latter in direct connection a resistance layer havingrelatively high resistance and on this in turn in direct connection a second resistance layer having low specific resistivity and serving as a path for a wiper, wherein the first resistance layer represents the transverse resistors and the layer arranged there above the longitudinal resistors of a continuous ladder network.

OBJECTS AND FEATURES OF THE INVENTION Objects of the invention are the provision of a layer voltage divider of the above described type which requires relatively little space, which may be economicly manufactured and which shows close tolerances of its electrical values.

These and other objects are achieved by providing in accordance with the present invention a layer voltage'divider with at least one tap to which one or more impedances are additionally attached, and in which the impedance or the impedances are applied together with laterally extending taps to a supporting plate or an intermediate insulating layer, in which the'impedance or impedances are covered to the exception of said lateral taps by 'an insulating layer, and in which the resistance layer with taps is applied to this insulating layer with which the appertaining taps of the additional impedances are conductingly connected.

On account of this arrangement of the web resistor above the impedances, no additional area space is required for the latter and they may therefore be accommodated in the space of an ordinary rotary or slide voltage divider without additional expense or effort. The impedances can be made within close tolerances and they are protected against outside influences by the insulating layer.

For better use of the space and for accommodating several impedances, a further development or improvement of the present invention provides for the application of the additional impedances in at least two different planes separated by insulating layers. The impedances in the second plane are provided in the same manner with the laterally extending taps which are connected with the corresponding tap or taps of a resistance web applied to a second insulating layer.

For rendering the manufacturing method more effective, a still further development of the present invention provides that the additional resistors arranged in one plane are formed as layer surfaces of equal specific resistivity so that their production can be carried out in one common step. The dif- I ferent values of the additional resistors required by the application conditions can be achieved by corresponding formation on their areas, particularly their of length-to-width ratios.

80 as to achieve a frequency-dependent voltage division, a still further development of the present invention provides the use of reactances, particularly capacitances, as additional impedances. These capacitances are applied to a surface by different methods such as steaming-on or dusting-on methods or by the photographic etching method as more or less mutually interleaving copper surfaces.

The capacitances are, just as the additional resistor, provided with laterally extending taps which are conductingly connected with the corresponding taps of the layer resistance web.

The invention is applicable to layer voltage dividers of any construction suchas to rotary, slidable or shaft dividers, and it represents a noteworthy progress in this field of technology.

THE DRAWINGS The invention and its details as well as its advantages will be more easily understood from the following description of two embodiments given as examples and from the diagramatic illustration of these embodiments in the attached drawings.

In the drawings FIG. 1 is a plan view of a supporting plate with conducting silver webs representing one embodiment of the invention FIG. 2 is a plan view of the same supporting plate having the resistance and capacitance layers applied thereto FIG. 3 is a plan view of the supporting plate of FIG. 2 after application of the insulating layer FIG. 4 is a plan view of a supporting plate according to FIG. 3 after application of the resistance web FIG. 5 is a plan view of a supporting plate provided with conducting silver webs representing a second embodiment of the invention FIG. 6 is a plan view of the supporting plate of FIG. 5 with the resistance layer applied thereto FIG. 7 is a plan view of the supporting plate of FIG. 6 after the application of the insulating layer and FIG. 8 is a plan view of the supporting plate of FIG. 7 having three resistance layers and three insulating layers and one resistance web.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS Turning now to FIGS. 1 through 4 illustrating a first embodiment of the invention, there is an elongated rectangular insulating plate 1 made of hard paper. A lead-in tap 2 and a lead-out tap 3 of conducting silver are applied in a first manufacturing step to this plate 1 as shown in FIG. I. T- or L- shaped taps 5,6 of conducting silver are provided opposite the arm of the L-shaped lead-in tap 2, which extends nearly over the entire length of the plate 1 of insulating material. Holes 4 are enclosed by all the taps along one longitudinal side of plate I, which later on receive the connecting soldering lugs with rivet attachment. The conducting silver layer is pre-dried in a drying-oven or -fumace.

In a further manufacturing step, a printing step, a resistance layer surfaces 8 and capacitance layer surfaces 7 are applied as shown in FIG. 2, so that they partly overlap the long arm of the lead-in tap 2 and the taps 5, 6. The layer 8 have equal specific area resistivity. Materials useful in this dielectric layer are metal oxides, such as tantalum oxide and aluminum oxide. By a drying step, the resistance layer 8 is hardened or cured.

An insulating layer 9, shown in FIG. 3, is applied by a further printing procedure in such a manner that it covers the layers 7, 8, but leaves free the lead-in and lead-out taps 2, 3 and the taps 5, 6. This insulating layer 9 is likewise cured or hardened in a drying step.

A resistance web 10 is applied by means of a final printing step so that it contacts by lugs 10 and 10" the taps 2, 3, 5, 6 at the places hitherto kept free of insulation whereby the resistor Sand capacitance 7 are connected in parallel with the respectiveweb sections. A concluding druing step cures this resistance web 10. I

A resistance web 10 is applied by means of a final printing step so that it contacts by lugs 10 and 10" the taps 2,3,5,6 at the places hitherto kept free of insulation whereby the resistors 7,8 are connected in parallel with the respective web sections. A concluding drying step cures this resistance web Soldering lugs, not shown, are then fastened by rivets in the holes 4. a

The desired component voltage is taken off the resistor web 10 by a wiper (not shown) along the dot-and-dash line 10a in FIG. 4.

The second embodiment, as shown inFlGS. 5 to 8, has again an elongated rectangular insulating plate 1 of hard paper (FIG. 5) provided with lead-in tap 11 and lead-out tap 12, both extending transversely to the longitudinal direction of plate land being formed as webs of conducting silver. A resistance layer 13 is applied in a further manufacturing step (FIG. 6) between the two webs 11 and 12 and fonned with a laterally projecting extension 13'. This resistance layer is cured by a drying step.

Thereupon, an insulating layer 14 is applied so that on the side of the lead-in tap l 1 a narrow strip of the resistance layer 13 there below remains free (FIG. 7) of insulation.

In further steps, such as they are described in connection with the first embodiment of FIGS. lto 4, resistance layers 15,17 with their lateral extensions 15',l8' and insulating layers 16,18 interposed there between are applied.

A resistance web is so applied that it is conductingly connected with the lead-out tap 12 and extends on the side of lead-in tap 1'1 nearly to but short of the end of the uppermost insulating layer 18. Lateral extensions 21,22,23 are conductingly connected withthe laterally extending projections 13, I5, 17 of the additional resistors 13,15,17. A conducting silver strip 19 is, by a final printing step, so applied over the exposed staggered ends of the resistance strips 13,15,17 that the latter, the resistance web 20 and the lead-in tap are in conducting connection;

Here, too, the desired component voltage is taken off by means of a wiper (not-shown) along the dot-and-dash'line 24.

While particular embodiments of the invention have been shown and described, it will be understood that various modifications may be made without departing from the true spirit and scope of the invention. The appended claims are, therefore, intended to cover any such modifications.

What is claimed is: 1. In a layer voltage divider: a supporting plate; a a resistance web being applied on said plate and having at least one connecting tap; at least one additional impedance being provided with a laterally projecting connecting tap and applied to said plate;

' an insulating layer being interposed between said resistance web and said impedance to the exclusion of their said connecting taps; and said tap of said resistance web and said tap of said impedance conductingly overlapping each other. 2. In a voltage divider of claim 1: a plurality of impedances; and insulating layers interposed between said impedances and between one of said impedances and said resistance web. 3. In a layer voltage divider of claim 1 having additional layer resistors applied as impedances in one plane.

4. In a layer voltage divider of claim 3 having said additional layer resistors of equal specific area resistivity.

5. In a layer voltage divider of claim 1 having at least one reactance applied in one plane.

6. In a layer voltage divider of claim 5 having said reactance constituted by a capacitance of addition.

* I a I 

1. In a layer voltage divider: a supporting plate; a resistance web being applied on said plate and having at least one connecting tap; at least one additional impedance being provided with a laterally projecting connecting tap and apPlied to said plate; an insulating layer being interposed between said resistance web and said impedance to the exclusion of their said connecting taps; and said tap of said resistance web and said tap of said impedance conductingly overlapping each other.
 2. In a voltage divider of claim 1: a plurality of impedances; and insulating layers interposed between said impedances and between one of said impedances and said resistance web.
 3. In a layer voltage divider of claim 1 having additional layer resistors applied as impedances in one plane.
 4. In a layer voltage divider of claim 3 having said additional layer resistors of equal specific area resistivity.
 5. In a layer voltage divider of claim 1 having at least one reactance applied in one plane.
 6. In a layer voltage divider of claim 5 having said reactance constituted by a capacitance of addition. 